Some cliff-hangers rely on one tried-and-true storyline, like a baby being born. House uses three. After realizing he's only imagined his hookup with Cuddy (it was all a dream!) he kicks Vicodin (a new beginning!) and checks into a mental hospital (the doctor becomes the patient!). If he hears the Lost numbers while in the mental ward we are totally done with this show.
2 of 13 NBC
Follow us here. Sylar kills Nathan. Peter tranquilizes Sylar. Parkman erases Sylar's memories and makes the shape-shifting, skill-splitting serial killer believe he is Nathan, thus spelling the end for Sylar for good. Or for at least three minutes, as "Nathan" soon shows hints of Sylar when he becomes fixated on a clock that is running fast in his office. Look for an epic internal battle between those two in Season 4.
3 of 13 Ron Tom/ABC
After wrapping up the overlong crazy Dave plot with a Mike-Susan liplock, the flash-forwarded fifth season wraps up with Mike saying "I do" to his blushing bride. But is the lady in the veil Susan or Mike's original wife-to-be Katherine? Apparently, viewers aren't the only ones still guessing — creator Marc Cherry is reportedly still undecided on which way to go.
4 of 13 Scott Garfield/ABC
Just when things were looking up — Izzie regains her memory after a risky surgery and George finds purpose in his life by joining the Army as a trauma surgeon — Izzie crashes and Meredith realizes the John Doe who's been run over by a bus is O'Malley. Sure, we heard all the stories about Katherine Heigl's and T.R. Knight's statuses on the show being up in the air, but seeing Gizzie together in that maybe-dream-maybe-death elevator was moving stuff.
5 of 13 Fox
The mysterious, robot-armed Nina Sharp promises Agent Dunham an audience with the equally mysterious Dr. William Bell if she stops David Robert Jones from crossing over into another dimension. Olivia succeeds, which earns her a one-way trip to Dr. Bell's office (what's up, Leonard Nimoy?), which exists in another dimension, a dimension in which the World Trade Center towers never fell and the Obamas are moving into the "new" White House. In other news, Walter visits Peter's grave. What's that? Peter's not dead? So then what is he?
6 of 13 Mario Perez/ABC
After a time-tripping season that reunited the Oceanic 6, er, 4, with the Lostaways in Dharma Initiative 1977, resurrected John Locke (sort of) and introduced the mysterious Jacob, Jack & Co. try to set everything back to normal by detonating a nuke at the Swan construction site. Too bad it didn't go off when they dropped it in, forcing Julie — who we believed fell to her death — to beat the hell out the bomb until the screen goes white, leaving us with eight months to wonder just who will survive the aftermath.
7 of 13 CBS
Ziva's not-so-happy homecoming in Israel gets much worse as in the final moments of the finale, we see her battered and bruised after being taken hostage by terrorists. Who has taken her prisoner, and how long will she be held captive?
8 of 13 Kelsey McNeal/Fox
Although ass kicker Jack Bauer accepted that his deteriorating health was going to be his undoing, his daughter Kim stepped in at the last minute to volunteer for a risky stem cell procedure. Will it be enough to save Jack for another 24 hours of world saving in Season 8? (Of course it will, but, you know.)
9 of 13 Michael Desmond/The CW
After much of West Bev High turns their back on Annie at the ridiculous post-prom party, she grabs a bottle of vodka and hits the road. During her tear-stained trek, she runs over something — a person? a squirrel? the show's believability? — but drives away from the scene. Unfortunately for Annie, somebody else saw it all go down.
10 of 13 Fox
Bones rattled viewers by sewing up Season 4 with the three little words Brennan-Booth 'shippers never wanted to hear: "Who are you?" Has Booth emerged from his post-brain surgery coma with no memory of his partner in crime-solving? Capping an episode that existed purely on the pages of a book Bones was writing, the twist left many wishing they could "forget" the preceding 59 minutes.
11 of 13 Vivian Zink/CBS
While other season finales give characters a figurative date with the reaper, Criminal Minds went for a literal approach. Having just cracked the case of the mass-murdering Turner brothers, Hotch returned home only to be confronted by The Reaper (guest star C. Thomas Howell). Was Hotch felled by the season-ending gunshot? See you in September....
12 of 13 Karen Neal/ABC
Did Addison really hurl the Hippocratic Oath into the trash can by bailing on her patient? Has Naomi really sided with the "enemy"? Pfft. Those dilemmas don't hold a candle to the WTF moment pregnant Violet is in the midst of, with a crazed patient poised to extricate her baby right from her belly!
13 of 13 Michael Courtney/The CW
"Clark Kent is dead." So it was announced by... Clark Kent, who realized that to fully embrace the super guy inside of him, he must remove his mild-mannered self from the equation. How will Lois react to the loss of her coworker/soul mate? Oh, right — she's truly out of the mix, having teleported through time to god knows when!